Telephone-transmitter.



No. 769,702. PATENTED SEPT. 18, 1904. J. W. LATTIG & O. L. GOODRUM.

TELEPHONE TRANSMITTER.

APPLICATION FILED JUNE 6, 1903.

N0 MODEL.

UNTTEE STATES Patented September 13, 1904:.

ATENT OFFICE.

JACOB IV. LATTIG, OF IVEST BETHLEHEM, AND CHARLES LANE GOODRUM,

OF PHILADELPHIA, PENNSYLVANIA, ASSIC NORS TO EASTERN TELE- PHONE MANUEACTURING COMPANY, OF \VESTCHESTER, PENNSYL- VANIA, A CORPORATION OF PENNSYLVANIA.

TELEPHONE-TRANSMITTER.

SPECIFICATION forming part of Letters Patent N0. 769,702, dated September 13, 1904.

Application filed June 6, 1903. Serial No. 160,324. No model.)

Be it known that we,JAcoB\V. LATTIG, residing in Vest Bethlehem, county of Lehigh, and CHARLES LANE GooDuUM, residing in Philadelphia, county of Philadelphia, State of Pennsylvania, citizens of the United States, have jointly invented a new and useful Telephone- Transmitter, of which the following is a specitication.

Our invention relates to granular telephone-transmitters, and has for its object the provision of means whereby the electrodes with their attaching devices and the interposed granular material may be combined and inclosed in a self-contained unit possessing high initial resistance and enabling sharp changes of considerable magnitude to be produced in the line-current.

In designingcircuits forso-called"common battery systems the transmitter becomes an important factor to consider. It is important that the initial or normal resistance of the transmitter should not be too low as compared with that of the line and of other apparatus; but it more important that the changes of resistance in the transmitter should be of a high order of magnitude as compared with the resistance of said line and other apparatus. "0 have produced what may be called a multime-chamber transmitter.each chamber containing a pair of electrode-faces with interposed granular material and all the chambers and their inclosed electrodes beingsupported in substantially a right line between the center of the diaphragm and the rear support-or bridge, the connections being such that pressure between the terminal or end electrodes is transmitted uniformly through the intervening chambers, the compression and expansion produced in each chamber being-little, it any, less than that between a single pair of electrodes in the ordinary transmitter and the unitary changes of resistance thus produced being added to give large total changes by connecting through all the chambers in series. Our transmitter may have two or more chambers containing four or more electrode-faces. Its etticiency is equal to that of a single pair instrument multiplied by the number of chambers, the losses in the inter- 5 mediate parts being apparently negligible.

Our invention is illustrated in the accompanying drawing, wherein the ligure shows a double-chamber resistance button or unit mounted in a transmitter of the solid-back type, the electrode-stems showing solid and other parts in section.

Referring to the drawing, A is the usual heavy cast front plate upon which the working parts of the instrument are mounted. This has a central opening to receive the threaded mouthpiece B, of hard rubber or similar material. On the rear face the plate has an annular peripheral flange (1, within which is seated the diaphragm I), surrounded 5 and insulated by the rubber gasket (Z. The diaphragm is secured in place by means of the usual insulated springs and has the ordinary damper-spring resting upon it, none of which are shown, as they form no part of the 7 present invention and would complicate the drawing unnecessarily.

Secured to the flange (1, preferably by screws 0 is the bridge C, having the central boss the binding-screw 0 the rubber bushing a, and the set-screw a".

Between the diaphragm and the bridge is mounted the multiple-unit resistance-chamber E, consisting of a metal cylinder 0 having an insulating-lininge and mica heads or auxiliary diaphragms. The insulating-lining e is divided into two end sections, between which is placed a hard-carbon partition 0, each halt of the lining thus constituting a. distance-piece, keeping the partition in its 5 proper position to divide the inclosure into two equal chambers.

The auxiliary diaphragms are lettered e and e and are preferably made of mica; but'they may be made of thin metal or other material, 9 the cooperating parts being insulated if metal is employed. e have shown the auxiliary diaphragms secured to the casing or cylinder 6 by having the edges of the latter knurled or spun over upon them, the lining e resting snugly against their inner faces. Each mica diaphragm has a central opening through which is passed the stem of one of the electrodes, these electrodes 6 and e lying snugly against the inner faces of the diaphragms, and clamping-nuts e and 6 respectively, being screwed down upon the stems from the outside, so that the electrodes are rigidly connected to the diaphragms, with their stems protruding axially therefrom in opposite directions. Granular carbon partly fills each chamber between the electrode and the central carbon partition.

In assembling the instrument the stem 6 is placed within a central opening in the main diaphragm D, so that the latter rests on a shoulder on the stem, and a nut or nuts 6 screwed down thereon. -The other stem, 6, is passed through the central opening in the boss 0 and after adjustment is secured therein, as by the set-screw c.

The circuit connections are made by one wire, 1, passing through the bushing 0' to the stem 0 or the diaphragm and the other wire, 2, passing to the screw 0 The circuit is then from wire 1 to the electrode 6 through the granular carbon to the partition e again through the granular carbon to the electrode 6 by the stem 0 to the bridge O, and to wire 2, or the reverse.

In operation the movements of the main diaphragm D are communicated to the electrode e and thence through both bodies of carbon and the intermediate partition. The partition moves synchronously with the elec trode e partly by reason of the varying pressure exerted on it through the first body of carbon and partly by reason of its connection through the cylinder 6 and the auxiliary diaphragm e. The distance between each electrode-face and the partition is substantially the same as in the standard types of solidback transmitter, and we have found that the articulation of this instrument is equal to the best heretofore produced, while the amplitude of the changes is practically doubled.

Having thus described our invention, what we claim, and desire to secure by Letters Patent of theUnited States, is

1. In a telephone-transmitter, a diaphragm, an electrode mounted thereon, a rigidly-supported electrode mounted in opposition thereto, an intermediate electrode or partition supported upon and between the first two electrodes, and independent bodies of granular material between the electrodes, substantially as described.

2. Ina telephone-transmitter, a movable electrode, a fixed electrode, an intermediate partition supported upon and between them, and a body of granular conducting material between each electrode and the partition, substantially as described.

3. In a telephone-transmitter, a diaphragm, a movable electrode supported thereon, a frame supporting the diaphragm, and a fixed electrode supported in said frame, flexible connections between and supported upon the electrodes, an intermediate conducting-partition supported thereby, and a body of granular conducting material between each electrode and the partition, substantially asdescribed.

4:. A multiple-unit resistance chamber or button fortelephone-transmitters comprising a shell or casing, flexible heads or diaphragms secured thereto and an intermediate conducting-partition therein, electrodes mounted on the heads with their conducting-faces inward, and granular material between each electrode and the partition.

In witnesss whereof we have hereunto signed our names in the presence of two subscribing witnesses.

JACOB w. LATTIDG. CHARLES LANE GOODRUM.

Witnesses:

M. S. LEWIS, EDWARD E. CLEMENT; 

